The present invention relates generally to material handling systems and methods. More particularly, the present invention pertains to sample handling methods and systems, such as, for example, those associated with processing systems (e.g., analysis systems such as systems designed to make surface measurements of samples, systems for performing deposition processes, etc.).
Various loading systems are available for providing a sample into a process chamber (e.g., a process chamber held at below or above atmospheric pressure), such that the sample introduced into the process chamber can be analyzed by an instrument, any other process can be carried out with respect to the sample using one or more other process tools. For example, such analysis instruments may include scanning electron microscopes (SEMs), instruments for performing elipsometry, instruments for performing transmission electron microscopy (TEM), instruments for performing scanning transmission electron microscopy (STEM), instruments for performing secondary ion mass spectrometry (SIMS), instruments for performing x-ray photoelectron spectrometry (XPS, also known as electron spectroscopy for chemical analysis (ESCA)), instruments for performing auger electron spectrometry (AES), or any other instruments for use in measuring of one or more properties of a sample (e.g., instruments using electron beams, etc.). Further, for example, other process tools may include etching tools, deposition tools (e.g., atomic layer deposition (ALD) tools, chemical vapor deposition tools, etc.), implant tools (e.g., ion implantation tools), etc.
A conventional loading system and method are shown generally in FIGS. 1 and 2A-2C. For example, as shown in FIGS. 2A-2C, a conventional loading system 430 includes a transfer apparatus 442 that is employed to load a sample 431 (e.g., a transferable work piece) into a process chamber 432 so that measurements may be taken when the process chamber 432 is held at below or above atmospheric pressure (e.g., a high vacuum (HV) or a ultra-high vacuum (UHV) environment), or is held at any other conditions different than ambient conditions.
The process chamber 432 is generally associated with a work piece manipulator 452 and is generally configured for modification of the pressure therein (e.g., with use of a pump, not shown). The process chamber 432 is generally separated from the loading system 430 by a load lock isolation valve 434.
The loading system 430 includes a load lock chamber 436 for receiving a work piece 431 and configured in a manner such that the pressure within the load lock chamber 436 may be made equal to that of the process chamber 432 prior to transfer of the work piece 431 into the process chamber 432. The load lock chamber 436 generally includes a load lock cover 438 which can be removed such that a sample 431 (e.g., transferable work piece) may be positioned therein. Further, the load lock chamber 436 includes a load lock pumping port 440 for use in bringing the load lock chamber to a pressure above or below atmospheric pressure.
The transfer apparatus 442 of the loading system generally includes a transfer probe 444 having at least a portion thereof (e.g., transfer holding device 445) which is positioned in the load lock chamber 436 for receiving or holding the sample 431 therein. In addition, the transfer apparatus 442 includes a transfer probe actuator 446 for moving the transfer probe 444 such that the sample 431 can be repositioned from the load lock chamber 431 to within the process chamber 432 (e.g., positioned on work piece receiver element 451 of work place manipulator 452).
The conventional loading system 430 shown in FIGS. 2A-2C may be used in the conventional transfer and process method 400, as shown and described with reference to FIG. 1. The transfer and process method 400, shown in FIG. 1, generally may be initiated by providing a sample 431 on the transfer holding device 445 associated with transfer probe 444 in load lock chamber 436 under ambient conditions (block 402). For example, load lock cover 438 may be removed and a sample provided that is to be held by transfer holding device 445.
With the sample 431 positioned in the load lock chamber 436, the load lock chamber 436 may be sealed and evacuated (block 404). With the pressure in the load lock chamber 436 equal to the pressure in the process chamber 432, the isolation valve 434 between the load lock chamber 436 and the process chamber 432 is opened (block 406). The transfer holding device 445 associated with transfer probe 444 is advanced to the processing position (e.g., analysis position) within the process chamber 432 (e.g., using transfer probe actuator 446) (block 408). The sample 431 is then transferred to the work piece receiver element 451 of the manipulator 452 associated with the process chamber 432 (block 410). For example, the manipulator 452 may be moved such that work piece receiver 451 is positioned for receiving sample 431 thereon. Following transfer of the sample 431 to the manipulator 452, the transfer holding device 445 is retracted using transfer probe 444, and the isolation valve 434 is closed between the load lock chamber 436 and the process chamber 432 (block 412). In such a manner, the pressure in the process chamber 432 is substantially maintained.
With the sample 431 in the process chamber 432, processing (e.g., analysis) may be performed thereon (block 414). For example, one or more surface measurements may be taken using one or more different types of analysis instruments associated with the process chamber 432. For example, XPS analysis may be performed in high vacuum or ultra-high vacuum environments of the process chamber 432 by a suitable instrument configured for use in analysis of a sample 431 within process chamber 432.
After completion of processing (e.g., analysis) (block 414), with the load lock chamber 436 evacuated to be at the same pressure as the process chamber 432, the isolation valve 434 is opened (block 416). The transfer holding device 445 is advanced using transfer probe 444 and transfer probe actuator 446 to the processing (e.g., analysis) position within the process chamber 432 (block 418) so as to receive (e.g., grasp) or otherwise become associated with sample 431 (block 420). With the sample transferred from the manipulator receiver element 451 in the process chamber 432 to the transfer holding device 445, the transfer holding device 445 is retracted back into the load lock chamber 436 using the transfer apparatus 442, and the isolation valve 434 is closed between the load lock chamber 436 and the process chamber 432 (block 422). As the process chamber 432 is isolated from the load lock chamber 436, the load lock chamber 436 may be brought to atmospheric pressure (e.g., pressurized), opened, and the sample 431 may be removed (block 424). A new sample may then be provided into load lock chamber 436 and the process repeated (block 426).
Such a conventional loading system 430 includes many components to accomplish the transfer into the process chamber 432 without loss of pressurization within the process chamber 432. For example, a separate transfer apparatus and isolation valve are required components of the loading system and add significant cost to such a system. Further, with use of such a conventional delivery or loading mechanism utilizing an isolation valve, significant pumping time is required to bring the load lock chamber 436 and its associated components to a suitable state above or below atmospheric pressure in order to equal that of the process chamber 432. Such a large pumping time decreases the speed of sample introduction.
The work piece manipulator 452 in such conventional systems generally needs to be converted for receipt of various different types of samples that are introduced therein. As such, the process chamber 432 needs to be opened thereby exposing it to atmosphere and requiring recovery procedures when different types of samples are to be introduced. In addition, any auxiliary functions, such as sample heating and cooling that are required in both the load lock chamber and the process chamber (e.g., at the introduction and analysis positions), require separate hardware to perform such functions. For example, hardware for heating or cooling the sample must be provided in both the load lock chamber and the process chamber.
Yet further, conventional loading systems have one or more of the following shortcomings. Load lock volume is large requiring a longer time to achieve pressure equalization. For example, as described above, the transfer mechanism adds to load lock volume and has a mechanism which interferes with pressure equalization. Further, use of a transfer probe must be accurately positioned in the process chamber to permit reliable transfer, and the work piece manipulator must be accurately positioned with respect to the work piece or sample on the transfer probe to permit reliable transfer. In other words, overall, loading reliability is undesirably low.
Further, other shortcomings of such conventional transfer systems are apparent. For example, a remote clamping mechanism must be provided on the manipulator to hold the sample securely within the process chamber. Clamping mechanisms have low rigidity to prevent sample vibration and low transfer position repeatability. Yet further, conventional systems are fairly large in size due to the number of components and type of components used therein. Overall system vibration is much greater because of the use of the transfer probe and such other additional components necessary for carrying out the functionality of such a conventional loading system.